Method for the production of apertures in polystyrene foam sheet

ABSTRACT

A method and apparatus for producing apertures such as ventilation holes and the like in a preformed sheet of polystyrene foam which comprises forming slits which extend completely through the foam structure, the slits being arranged in a predetermined pattern, and passing the preslit foam through a heating zone such as a preheat oven used in plastic thermoforming operations. The resultant heated sheet of foam, as it emerges from the oven, is characterized by having a plurality of openings or apertures in locations corresponding to the slits which were made in the foam prior to preheating. The aperture containing sheets may be subsequently subjected to a thermoforming operation whereby thermoformed objects such as produce containers are produced having ventilation openings, i.e. apertures, located in a predetermined disposition around the thermoformed tray structure.



